评述异常压力研究中的石油地质学新思想

在对异常压力的认识不断深化的过程中,凝结出许多新的概念和思想,为现代石油地质学理论注入了新的内容。关于超压生成与有机质成熟-生烃的关系虽有争议,但大多数主张超压对有机质成熟和生烃起抑制作用;在超压的背景下,生烃、排烃以及烃类的运移和聚集常呈现出幕式的特征;压力驱动是流体活动和油气运移的重要动力;动态运移通道是油气运移的新型通道;通常压力过渡带是油气聚集的有利场所;在超压的含油气盆地中,可能发现的非传统油气聚集有异常压力的气饱和封存箱、水力破裂-泥岩裂缝油气藏、烃水倒置的油气藏等。异常压力的储层具有相对独立性。

REVIEW OF NEW IDEAS OF PETROLEUM GEOLOGY ASSOCIATED WITH ABNORMAL FLUID PRESSURE SYSTEM

Many new ideas and concepts were proposed as a consequence of development in the abnormal fluid pressure studies, which have been promoting the advance of modern petroleum geology. On the problem of the relationships between abnormal pressure and hydrocarbon generation, majorities agreed with overpressure retardation of organic matter maturation and petroleum generation. The retardation is also favorable for the preservation of hydrocarbon. Under the condition of overpressured environments, hydrocarbon generation, expulsion, migration and formation of pools are always charactered by episodic pattern. Pressure driving force is a significant dynamic condition for fluid flow and hydrocarbon migration. In the overpressure environments, the dynamic migration routes that include hydraulic fractures, faults and fluid diapir structures may occur as consequence of hydrocarbon generation and overpressure development. The coincidence of excess porosity associated with overpressure is very commom. Most hydrocarbons production occurred in the transition zone between hydropressured and overpressured sediments. This knowledge has been provided a new approach to exploration in most sedimentary basins.  Unconventional hydrocarbon accumulation associated with abnormal pressure system, such as anomalously pressured tight gas sand or sweet-spots, hydraulic fracture-fractured shale reservoirs, and pools with petroleum overlain by water can be found in abnormally pressured sedimentary basins.